The discussion board rules do not allow for planning to circumvent disney rules or regulations. We don't know why the PP was permitted to ride when they did not have a reservation, but the policy is no reservation (on arrival and departure day) no ride.Bingo!
We are a community here, so it would be great if someone would step up to help out the OP. If the OP posts the date they want to ride the DME, and the resort they want to ride from, then a DISer who recognizes that they can help can contact the OP privately via DM, and make the the appropriate arrangements, similar to what the OP's friend experienced.